Field of the Invention
The present invention relates to wireless communication, and more particularly, to a method of discovering and announcing a service supported in a wireless local area network (WLAN) system, and an apparatus supporting the method.
Related Art
With the advancement of information communication technologies, various wireless communication technologies have recently been developed. Among the wireless communication technologies, a wireless local area network (WLAN) is a technology whereby Internet access is possible in a wireless fashion in homes or businesses or in a region providing a specific service by using a portable terminal such as a personal digital assistant (PDA), a laptop computer, a portable multimedia player (PMP), etc.
The institute of electrical and electronics engineers (IEEE) 802.11n is a technical standard relatively recently introduced to overcome a limited data rate which has been considered as a drawback in the WLAN. The IEEE 802.11n is devised to increase network speed and reliability and to extend an operational distance of a wireless network. More specifically, the IEEE 802.11n supports a high throughput (HT), i.e., a data processing rate of up to 540 Mbps or higher, and is based on a multiple input and multiple output (MIMO) technique which uses multiple antennas in both a transmitter and a receiver to minimize a transmission error and to optimize a data rate.
In an infrastructure WLAN system environment managed by an access point (AP), a station (STA) may receive from the AP a service desired to be received by a user. The STA may query whether the AP is capable of providing a specific service to receive the service, and may determine whether the service can be provided by receiving a response from the AP. Accordingly, the STA can receive the specific service from the AP.
The STA may also receive a service from another STA which coexists in the WLAN system. This may more frequently occur in a WLAN system in which the STA is increased in number and thus many STAs coexist. For this, the STA may query to another STA whether a service can be performed, and may determine whether the service can be provided by receiving a response thereof.
A procedure for service discovery may be performed mutually exclusively with respect to an operation when a service is provided in practice. For example, radio signal transmission/reception for the service discovery also occupies a channel, and accordingly, channel occupation may be excluded for data transmission/reception when the service is provided in practice. This may result in a decrease in efficiency of a WLAN service.
In addition, the STA consumes power due to the procedure performed for the service discovery. In particular, from a perspective of an STA which operates on a battery basis, an operation performed for the service discovery or an operation performed always in an awake state as a response regarding whether a service can be provided may be a cause of unnecessary great power consumption.
Accordingly, there is a need for a service discovery method capable of solving an unnecessary power consumption problem and a problem related to a deterioration in WLAN service efficiency and capable of providing a service in a more effective manner.